U.S. President Barack Obama is crediting “strong American diplomacy” for key milestones with Iran in a 24-hour period, including confirmation that Tehran has significantly rolled back its nuclear program, released American prisoners and resolved a three-decade-old financial dispute.

The president spoke on Sunday after receiving confirmation that all five Americans released by Iran had departed the country (watch the president's full statement at the following link).

“This is a good day,” Obama told the nation. After using diplomacy to directly engage with the Iranians “We’ve seen results,” he said.

On Saturday, the United States and five other global powers lifted sanctions on Iran after a report by the U.N. nuclear watchdog saying Tehran had fulfilled its commitments to cut back its nuclear program.

President Barack Obama speaks about the release of Americans by Iran, in the Cabinet Room of the White House in Washington, Jan. 17, 2016.

The removal of sanctions gives Iran access to funds ranging from $50 to $100 billion, according to senior administration officials.

The U.S. says Iran has removed two-thirds of its centrifuges to enrich uranium, shipped out more than 98 percent of its enriched uranium stockpile and will be subjected to unprecedented inspections and access to its nuclear program.

If Iran tries to covertly build a bomb, “we will catch them,” said the president. “The region, the United States, and the world will be more secure.”

Communication channels

The long and difficult diplomatic process to negotiate the Iran nuclear deal opened channels of communication for the first time in decades and new opportunities for the two nations to engage on other key matters, said senior administration officials.

The diplomatic ties established between Secretary of State John Kerry and his Iranian counterpart Javad Zarif during the nuclear talks are credited with helping to secure the prompt release of U.S. sailors captured by Iranians in the Persian Gulf last week.

US Secretary of State John Kerry (L) meets with Iranian Foreign Minister Javad Zarif (2R) in Vienna, Austria on Jan. 16, 2016, on what is being referred to as "implementation day," the day the IAEA verifies that Iran has met all conditions under the nuclear d

The historic engagement also led to the release of five Americans unjustly detained by Iran, said the president.

“After the nuclear deal was completed, the discussions between our governments accelerated,” said Obama, securing the U.S. detainees release as part of a prisoner swap on Saturday.

The former detainees include Jason Rezaian, a journalist for The Washington Post; Saeed Abedini, an Idaho pastor held for more than three years; former Marine sergeant Amir Hekmati of Michigan held for more than four years; Nosratollah Khosravi-Roodsari, and student Matthew Trevithick.

After the implementation of the Iran nuclear deal and the release of prisoners, Obama said the two countries settled a more than three-decade old claim by the Iranian government against the United States.

The agreement involves a $400 million trust fund Iran once used to buy military equipment before the two countries broke off diplomatic ties. The U.S. will pay the $400 million along with $1.3 billion in interest.

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Senior administration officials say the settlement could save the U.S. billions from potential higher awards.

The president also spoke directly to the Iranian people, saying “Yours is a great civilization.”

But for decades Iran has destabilized the region and isolated Iran from much of the world. “Following the nuclear deal, you -- especially young Iranians -- have the opportunity to begin building new ties with the world," Obama added.

New sanctions

Also on Sunday, the U.S. Treasury Department imposed new sanctions on five individuals and several companies for ties to Tehran's ballistic missile program.

"The nuclear deal was never intended to resolve all of our differences with Iran," the president said. "We will continue to enforce these sanctions vigorously," he added of the missile sanctions.

Earlier Sunday, Iranian President Hassan Rouhani says the Islamic Republic has entered a "new chapter" in its history in a speech Sunday praising the end of international sanctions imposed over Iran's nuclear activities.

A senior administration official said Sunday the U.S. continues to have “profound differences” with Iran over its support of terrorists, destabilizing actions in the region, human rights abuses and how to end to the war on Syria.

Iranian President Hassan Rouhani, left, presents a draft of the country's new budget and sixth development plan to the parliament speaker Ali Larijani in an open session of parliament, in Tehran, Iran, Jan. 17, 2016.

“We do believe we should test whether there could be dialogue with regard to other issues,” said the officials. “Frankly the main forum for that will be the Vienna process on Syria.”

Global powers are holding talks in Vienna about how to end the war and bring about a political transition in Syria. The U.S. and Iran remain deeply divided about whether Bashar al-Assad should play any role in Syria’s political future. The U.S. believe the war will not end as long as Assad remains in power.

But Saturday's news was greeted with skepticism by Israeli Prime Minister Benjamin Netanyahu, the most vocal opponent of the deal in the international community. He warned that "Iran has not relinquished its ambition to obtain nuclear weapons, and continues to act to destabilize the Middle East and spread terror throughout the world."

The end of sanctions was also greeted with scorn in the United States by many of Obama's Republican opponents, especially the party's 2016 presidential candidates.

"It seems to be an indication of where we are going. That Iran deal is the dumbest deal I think I’ve ever seen," said Republican presidential candidate Donald Trump at a recent campaign event.

A Falcon 900 of the Swiss Air Force presumed to be carrying carrying American prisoners released by Iran is pictured on the tarmac of Geneva's airport, on Jan. 17, 2016.

House Speaker Paul Ryan added to the criticism. "A bipartisan majority in the House voted to reject this deal in the first place, and we will continue to do everything possible to prevent a nuclear Iran," he said.

Chairman of the House Committee on Foreign Affairs Ed Royce welcomed the release of the detained Americans.

“All of them should have been unconditionally released a long time ago. Period,” he said.

But he added that “a disturbing pattern is emerging where the Obama administration is willing to negotiate the release of spies, terrorists and now criminals. I fail to see how this trend will improve the long-term security of the United States and its citizens.”

Value of diplomacy

Democrat Nancy Pelosi, the House minority leader said "While we have no illusions about the Iranian regime, we have once again seen the value of the enhanced diplomatic relationship created through our historic nuclear agreement."

Rouhani dismissed any criticism of the nuclear during his speech to the Iranian parliament. He said everyone is happy "except Zionists, warmongers fueling discord in the Islamic world, and hardliners in the U.S."

The deal is a triumph for Rouhani, considered a moderate cleric who was elected in 2013 on a pledge to reform his country’s economy. But Tehran's hopes of an instant windfall by its return to the global oil markets will likely be tempered due to the massive glut of oil, which dropped to $30 per barrel this week for the first time in a decade.